You probably spent a lot of money on your home’s appliances, so you might as well get the most out of them. Here are some of the most common myths and old wives’ tales about dishwashers, refrigerators, and other appliances.

The Mental Floss YouTube channel and host Elliott Morgan are here to debunk all those things you’ve heard through the grapevine about your home appliances. Things like the fact that dishwashers use quite a bit less water than washing dishes by hand, your coffee maker needs to be cleaned regularly (because the environment is perfect for mold and germs), washing clothes in cold water is just as clean as washing in warm water, you can keep your refrigerator running more efficiently by cleaning the coils once a year, and the water leftover at the bottom of your dishwasher is actually a good thing. The more you know about your appliances, the better you can use them.